Absolutely
And then theres the ones you recognise but not where from, smile a polite hello, maybe with a friendly wave so as not to offend by not remembering where you know them from.
And realise later on they are an actor off TV who doesnt know you from Adam.
Pfft I guess they are used to that anyway
(insomniac-surfer oh go on then, just this once, Sat 17 Jul 2010, 1:03, 1 reply)

Maybe they feel exactly the same way.
So they're walking past thinking, "Do I know that person?" rather than "Oh god, another fan..."

Unless they're an utter prick, of course. You get the impression with some actors that if their mother stopped them on the street, they'd give 'em an autograph.
(Sivvus trolley collision in the fruit aisle led to a jam, Sat 17 Jul 2010, 1:06, closed)

LOL
Yep met a few of those.

But also some very nice ones
I once had a very odd converation with someone i thought i knew about buying knickers.
( too long a story to relate here)
Afterwards someone said 'why were you talking knickers with him?'
erm why not?
Cos he's on (insert some famous soap opera)

oh, oops I thought he was someone I knew
(insomniac-surfer oh go on then, just this once, Sat 17 Jul 2010, 1:15, closed)